A Brett Kearney hat-trick helped Bradford take the victory at the Provident Stadium after Castleford had been reduced to 11 men. The Bulls themselves coped with the loss to the sin-bin of Danny Addy just before half-time and only led 20-12 midway through the second half before the Tigers had Justin Carney and Jamie Ellis yellow carded.
Bradford savoured plenty of possession throughout but Cummings said: "We were a bit edgy when we get down there (near the line). We're trying to score a try all the time when if we ask a few questions, we'll get there."
The Bulls capitalised on the short-handed Tigers to run in three tries in the final 10 minutes, with Kearney adding his second and third tries in the last three.
Castleford showed for long periods the kind of resilience that had earned them a shock 14-12 victory over champions Leeds the previous week, but eventually ran out of steam when their two backs were sin-binned towards the end of the match.
Cummins added: "We just need a little bit more direction at times.
"I liked some of the stuff - we were skilful and made a couple of good off-loads but our structure just went away from us at times."
Castleford coach Ian Millward was unhappy with some of the officials' decisions, having also lost Warrington loanee Gareth O'Brien on his debut for huge chunks of the game after a controversial clash with Nick Scruton early in the game.
Millward was guarded with his words, but said: "I'll have a look at everything but I was confused.
"But I'm not going to sit here and pinpoint the ones (decisions) I was concerned with."